One-Loop Effective Action for Spherical Scalar Field Collapse

We calculate the complete one-loop effective action for a spherical scalar field collapse in the large radius approximation. This action gives the complete trace anomaly, which beside the matter loop contributions, receives a contribution from the graviton loops. Our result opens a possibility for a systematic study of the back-reaction effects for a real black hole.Comment: 14 pages, slightly expanded version to appear in Class. Quant. Gra

Loop Corrections in the Spectrum of 2D Hawking Radiation

We determine the one-loop and the two-loop back-reaction corrections in the spectrum of the Hawking radiation for the CGHS model of 2d dilaton gravity by evaluating the Bogoliubov coefficients for a massless scalar field propagating on the corresponding backgrounds. Since the back-reaction can induce a small shift in the position of the classical horizon, we find that a positive shift leads to a non-Planckian late-time spectrum, while a null or a negative shift leads to a Planckian late-time spectrum in the leading-order stationary-point approximation. In the one-loop case there are no corrections to the classical Hawking temperature, while in the two-loop case the temperature is three times greater than the classical value. We argue that these results are consistent with the behaviour of the Hawking flux obtained from the operator quantization only for the times which are not too late, in accordance with the limits of validity of the semiclassical approximation.Comment: 20 pages, latex, no figure

Concept Based Knowledge Discovery from Biomedical Literature

Philosophiae Doctor - PhDThis thesis describes and introduces novel methods for knowledge discovery and presents a software system that is able to extract information from biomedical literature, review interesting connections between various biomedical concepts and in so doing, generates new hypotheses. The experimental results obtained by using methods described in this thesis, are compared to currently published results obtained by other methods and a number of case studies are described. This thesis shows how the technology, resented can be integrated with the researchers own knowledge, experimentation and observations for optimal progression of scientific research.South Afric

Unlocking the potential for regional collaboration in the ICT domain in the Western Balkans

Smart Specialisation has gained traction in the Western Balkans. In the last four years, all Western Balkan economies made progress in developing their first Smart Specialisation strategies. This development led to revealing preliminary or final priority areas in most of them, highlighting few potentially common ones for the entire region. This is the case with the ICT area which so far appeared in all finalised Smart Specialisation strategies as well as in the final analyses that provide priority areas that should enter the strategies. Having in mind that the Smart Specialisation-related documentation aim at providing justification for selecting priority areas, as well as thorough analysis of their potential for national economies, there was a need to identify common niches for collaboration in research and innovation efforts and to highlight the challenges that the economies are facing concerning exploiting their full potential in the ICT area. This report highlights main challenges and opportunities that were emphasised during the discussion. The report also gives an expert overview of the context and provides recommendation for facing these challenges and promoting collaboration in the Smart Specialisation priority area of ICT for the benefit of the entire region.JRC.A.3 - Member States Partnerships and International Relation

Modeling of thermoelectric module operation in inhomogeneous transient temperature field using finite element method

This paper is the result of research and operation modeling of the new systems for cooling of cutting tools based on thermoelectric module. A copper inlay with thermoelectric module on the back side was added to a standard turning tool for metal processing. For modeling and simulating the operation of thermoelectric module, finite element method was used as a method for successful solving the problems of inhomogeneous transient temperature field on the cutting tip of lathe knives. Developed mathematical model is implemented in the software package PAK-T through which numerical results are obtained. Experimental research was done in different conditions of thermoelectric module operation. Cooling of the hot module side was done by a heat exchanger based on fluid using automatic temperature regulator. After the calculation is done, numerical results are in good agreement with experimental. It can be concluded that developed mathe-matical model can be used successfully for modeling of cooling of cutting tools

DESM: portal for microbial knowledge exploration systems

Microorganisms produce an enormous variety of chemical compounds. It is of general interest for mi-crobiology and biotechnology researchers to have means to explore information about molecular and genetic basis of functioning of different microor-ganisms and their ability for bioproduction. To en-able such exploration, we compiled 45 topic-specific knowledgebases (KBs) accessible through DESM portal (www.cbrc.kaust.edu.sa/desm). The KBs con-tain information derived through text-mining of PubMed information and complemented by informa-tion data-mined from various other resources (e.g. ChEBI, Entrez Gene, GO, KOBAS, KEGG, UniPath-ways, BioGrid). All PubMed records were indexed us

MANGANESE-PYROMELLITATE COMPLEX AS A PRECURSOR FOR PREPARATION OF SPINEL Mn3O4

In recent years, thermal decomposition studies of transition metal complexes with benzenepolycarboxylate ligands have become an area of a great importance due to the possibility of obtaining useful metal oxides with desirable electrical, magnetic and catalytic properties [1]. As a contrast to conventional methods for the preparation of metal oxides, such as hydrothermal or sol– gel treatment, thermolysis is faster, more efficient and environmentally friendly. Mn(II)–dipya (dipya = 2,2’-dipyridylamine) complex with tetraanion of 1,2,4,5-benzenetetracarboxylic (pyromellitic, H4pyr) acid, [Mn2(dipya)2(pyr)(H2O)2], has been prepared and characterized by elemental, spectral and microscopy analyses. Direct thermolysis of the complex up to 1200 °C in an air atmosphere yielded spinel Mn3O4 oxide material. The obtained Mn3O4 has been characterized for its structural, spectroscopic, morphological and optical properties. The possibilities of using this oxide as photocatalyst or co-photocatalyst for removing textile organic dyes, as well as inorganic pigmentary material, were also investigated and discussed

Comparative study of Ag/ZnO nanopowders obtained by solvothermal and precipitation methods

Beside wide range of applications, zinc oxide is recently recognized as a promising photocatalyst mainly used to degrade organic water pollutants. The great advantage of ZnO over TiO2, which is the most common photocatalyst, is the absorption in wider solar spectrum, partly in the visible region [1]. Generally, the photocatalytic properties usually depend on the crystallinity and crystallite size, particle size, morphology and pore sizes, surface area, band gap energy, availability of active sites, number and nature of trapped sites, as well as on adsorption/desorption characteristics [2]. The modification of photocatalysts by noble metals can enhance their photocatalytic activity. This paper discuss the influence of synthetic method on photocatalytic activity of obtained powders. Solvothermal and precipitation methods were chosen for the preparation of Ag/ZnO nanopowders. For the first one, the Zn(CH3COO)2·2H2O with different AgNO3 content (0, 0.75, 1.5 and 3 mol.%) was solvothermally treated at 120 °C for 18 h in the presence of poly(vinyl pyrrolidone), ethylene-glycol and NaOH. The obtained samples were rinsed out with distilled water, centrifuged and dried at 105 °C for 3h. In precipitation method, Zn(CH3COO)2·2H2O was dissolved in ethylene-glycol in the presence of chitosan soluted in acetic acid, which was followed by addition of AgNO3 in the same quantity as used for the solvothermal synthesis. The obtained suspension was heated up to 150 °C for 2 h and then calcined at 400 °C for 1 h (Fig.1). The prepared samples were characterized by XRPD, FESEM, UV-vis techniques, while photocatalytic properties were tested on Reactive Orange 16 textile azo dye and compared to the commercial ZnO (the average particle size: 20 nm). 84 Based on XRPD, the predominant phase in all samples is ZnO with the weak reflections belonging to Ag for 0.75%Ag/ZnO, which become clearly visible for samples with 1.5 and 3% of Ag. The average crystallite size was calculated using Williamson-Hall method giving 20 ± 2 and 25 ± 2 nm for powders obtained by solvothermal and precipitation method, respectively. The calculated strains were insignificant probably due to low concentration of defects. On the other hand, this is not the case for commercial ZnO with strain of 0.25(3) %. This sample consists of nanoparticles with a slightly elongated spherical shape while all obtained ZnO nanopowders contain mutually similar nanoparticles with approximately spherical shape, which however create diverse forms of agglomerates. The average particle size was around 25 nm for solvothermally synthesized samples and approximately 30 nm for samples obtained by precipitation method. Comparing to both unmodified ZnO and commercial one, all prepared Ag/ZnO samples showed a broad band at 450 nm (visible region) which causes the narrowing of band gap. The existence of this band is the confirmation that metallic Ag particles were formed, as indicated by XRPD, since they can absorb visible light and activate photocatalyst in visible spectrum. The photocatalytic measurements showed that all synthesized nanopowders have higher adsorption power and photocatalytic activity than the commercial ZnO (Fig.1). This could be attributed to slightly elongated grains of commercial ZnO and the existence of significant strain. If compare the samples obtained by two different methods, Ag modified ZnO powders from solvothermal method are more efficient than the ones from precipitation method due to the smaller particles of silver.Larger Ag particles on ZnO could cause negative effects, such as light blocked, which result in the decrease of photocatalytic activity. The unmodified ZnO powders have the same efficiency regardless of the synthetic method. Comparing the photocatalytic activity of samples obtained by same method, the Ag distribution and its particle size seems to play the major role. Summary, no matter which procedure was used, 1.5% Ag/ZnO powders have performed the highest effciency in degradation of RO16. It means that the photocatalytic activity does not depend only on Ag content but the metal distribution is important as well. In this work, it is shown that the optimized content of Ag amounts about 1.5 mol.% regardless of synthetic method and it could be recommended for further research in terms of economy. References [1] B. Simović et al., J. Serb. Chem. Soc., 2014, 79, 1433. [2] B. Simović et al., Process. Appl. Ceram., 2017, 11, 27